Exercise device



FIG. 1 shows a front perspective view of an adjustable dumbbell.

FIG. 2 shows a bottom perspective view of an adjustable dumbbell.

FIG. 3 shows a side perspective view of an adjustable dumbbell.

FIG. 4 shows a side view of an adjustable dumbbell.

FIG. 5 shows a front view of an adjustable dumbbell; and,

FIG. 6 shows a top view of an adjustable dumbbell. 

CLAIM The ornamental design for an exercise device, as shown and described. 